Added tests for IP detection.

src/lib/__tests__/detect.test.ts

@@ -0,0 +1,21 @@
+import * as detect from '../detect';
+
+const IP = '127.0.0.1';
+
+test('getIpAddress: Custom header', () => {
+  process.env.CLIENT_IP_HEADER = 'x-custom-ip-header';
+
+  expect(detect.getIpAddress({ headers: { 'x-custom-ip-header': IP } } as any)).toEqual(IP);
+});
+
+test('getIpAddress: CloudFlare header', () => {
+  expect(detect.getIpAddress({ headers: { 'cf-connecting-ip': IP } } as any)).toEqual(IP);
+});
+
+test('getIpAddress: Standard header', () => {
+  expect(detect.getIpAddress({ headers: { 'x-forwarded-for': IP } } as any)).toEqual(IP);
+});
+
+test('getIpAddress: No header', () => {
+  expect(detect.getIpAddress({ headers: {} } as any)).toEqual(null);
+});